"Pépin" Carloman, roi d'Italie - Record of Alternative Data After Merges

Middle Name Carloman; 'de Carolus'
Surname de Lombardy; De Carloman
Birth Surname D'Italie; King of Italy (781-810)
Birth Date April 773; c. 4/12/781; 777
Birth Location Aachen, Nordrhein-Westfalen, Deutschland OR Rome, Italy

i'm not sure if i'm just half asleep here - but i'm not finding the evidence for the exact birthdate of April 773 that we have presently on the profile.

From what i can see a better birthdate to lock in on this field would be 777. Does anyone else want to give their input?

Extract from about me on the profile;
Birth: 777 - Frankish Empire (location is not specified by any reliable source). Aachen/Aix-la-Chapelle is not necessarily the safest guess either as Hildegard had Hludowic/Louis and Hlothar/Lothar at a villa called Cassino­gilum, believed to be Chasseneuil-du-Poitou in the present French Region Vienne, during her husband's Spanish campaign a year or two earlier, and died of complications from childbirth in Thionville three years after. Hildegard's residence was mobile, and there is no source pinpointing her location at the time of Pepin's birth.

Baptism: 15 April 781 - Rome, Lombard Kingdom (present Italy), Frankish Empire (same day as he was consecrated King of the Lombards under the regency of Adalhard - he was 4 years old). Supported by FMG and Wikipedia.

Promise you won't quote me on this? Somewhere in the deep reaches of my memory, so far buried it would take a great deal of effort to dredge out, is a vague idea that April 773 is a constructed date, pegged somehow to a contemporary chronicle or chronicles of events around his father leaving on a campaign. That is, his birth can be dated fairly precisely by reference to other known dates.

Good to have logged that possibility. Justin - thank you. Sooner or later someone else's memory will be jogged to confirm it.
For now, we can just note here that we still need to, if any user gets energetic and wants a research puzzle to track down in their spare time for the fun of it